Currently, a rail transit vehicle currently is a multi-marshalling vehicle. In a traditional situation, a signal among compartments of a train is transmitted via a jumper cable. In a case that a fatigue break fault occurs in a jumper cable among the compartments of the train, it is unable to transmit some key signals. In some special cases, the fatigue break fault of the jumper cable is concealed and is difficult to be troubleshot. Even a basic function such as train traction, braking, opening a door and closing the door can not be realized in a case of a serious fault, which seriously affects a normal operation of the train. Reliability of transmitting the signal among compartments of the train is low.